1638671 has 4 divisors (see below), whose sum is σ = 1650600. Its totient is φ = 1626744.

The previous prime is 1638653. The next prime is 1638673. The reversal of 1638671 is 1768361.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1638671 - 2¹⁴ = 1622287 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1638673) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5756 + ... + 6033.

It is an arithmetic number, because the mean of its divisors is an integer number (412650).

2^1638671 is an apocalyptic number.

1638671 is a deficient number, since it is larger than the sum of its proper divisors (11929).

1638671 is a wasteful number, since it uses less digits than its factorization.

1638671 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11928.

The product of its digits is 6048, while the sum is 32.

The square root of 1638671 is about 1280.1058549979. The cubic root of 1638671 is about 117.8955074194.

The spelling of 1638671 in words is "one million, six hundred thirty-eight thousand, six hundred seventy-one".